All Questions
24 questions
0
votes
1
answer
234
views
Ping from dummy interface
I want to test NAT table using dummy interface. I have enp1s0 interface connected to internet and have configured NAT table to MASQUERADE packets as shown below.
random@debian:~$ ip addr
1: lo: &...
0
votes
0
answers
64
views
linux ip route (interface) selection based on ping to destination?
Intro
I live in Thailand. Our connectivity to Europe here is somewhat strange.
Sometimes connections go directly to Europe (ping of 180-250ms), because my ISP has a direct 100G link to a peering ...
- 145
2
votes
1
answer
138
views
Ping device connected to host having LAN access
I've been playing back and forth routing games for a couple of days.
As it is quite hard to describe with words I made a diagram below:
What I want to achieve is being able to ping Rpi 4B from Rpi 3B ...
- 21
1
vote
1
answer
2k
views
ICMP/Ping works even after adding iptables drop rule
We have an application which will configure network interface as well as iptables rules based on user configuration. Please find the iptables rules after configuring with the application
Even after ...
- 111
-2
votes
1
answer
802
views
Ubuntu Firewall blocking DNS requests to VMWARE guest with outbound traffic rules added and stateful matching done
This is a unique problem related to DNS queries(tcp/udp 53) even with correct UFW/iptables rules and does not relate to /etc/resolv.conf
I can ping google DNS 8.8.8.8 but cannot resolve google.com ...
- 11
0
votes
1
answer
978
views
iptables and SNAT spoofing
So we are working with iptables at class and I've been testing some rules in the NAT table. As far as I know SNAT changes the IP source of a packet to which the rule dictates but what I tested does ...
- 1
1
vote
1
answer
3k
views
cannot ping specific interface from router: (sendmsg: Operation not permitted)
I have router that I built running Arch Linux and I have a strange problem that might point to a misconfiguration. Here is my setup:
LAN interface: intern1
WAN interface: extern1
LAN address: 192.168....
- 111
1
vote
1
answer
646
views
Cannot PING between two network interfaces
I am playing around AWS EC2 instance and I came across a strange problem.
I created an EC2 instance (Instance A) with 2 network interfaces, and the following is the routing table:
default via 172.31....
- 23
0
votes
0
answers
62
views
My server occasionally loses ability to ping (and site goes down)
I am running Nginx on Ubuntu (digitalocean) to host a wordpress site. Every now and again the site will completely go down (500 error) and when I ssh into the server (which I can do) to check it out I ...
- 101
0
votes
1
answer
296
views
IPsec: Can ping hosts of other network with the firewall but not with hosts behind the firewall
I have a endian firewall and a established IPsec tunnel. The firewall is in the network 192.168.100.0/24 and has the address 192.168.100.1. The hosts that I try to ping are in the network 10.4.0.0/32 ...
0
votes
1
answer
227
views
mongodb is reachable through each server but replica sets cannot find each other after iptables
I have 9 machines where I set up mongod replset instances. I set iptables so servers can see each other and i can confirm this sshing into one server and connecting to a mongod in another server. But ...
- 113
19
votes
1
answer
5k
views
Why is ping working when all incoming and outgoing connections are blocked in the firewall?
I have DENIED both incoming and outgoing connections using ufw on Debian VPS. There is only one rule defined, which is to allow connection to SSH port.
ufw is enabled and working.
Yet I am still ...
- 789
1
vote
1
answer
100
views
Block Clients based on RTT
I am running an application on my Debian server, which uses IPv4 and UDP for data communication.
I would like to block every client for a short while, that has a Round Trip Time above 140ms.
...
- 92
1
vote
1
answer
4k
views
Don't get ICMP reply when ping from specific interface
I have a linux machine running under CentOS with 2 ISP. My rollover ISP channel script try to determine when we at secondary ISP channel is there a primary ISP channel get up and vice versa when need ...
user419775
4
votes
1
answer
471
views
OpenVPN Access Server: Remote Subnet Cannot Access Client's Resources
I have OpenVPN Access Server running on AWS. Here's the configuration:
172.18.16.0/20
Client (172.18.16.101) ----- OpenVPN Server (172.16.0.0/20)
|
...
- 61
0
votes
1
answer
5k
views
How to route traffic between 2 VLANs on different subnet
I have the following problem:
I have one interface eth0 with IP 172.20.51.61/24
I have configured 2 VLANS on the same machine:
eth0.120 : 172.20.52.61/24
eth0.200 : 172.20.54.61/24
I also have a ...
- 115
-1
votes
3
answers
33k
views
Web server is working, but ping returns a request timeout for icmp_seq [closed]
these are my current iptables settings:
Chain INPUT (policy DROP)
target prot opt source destination
ACCEPT all -- anywhere anywhere state ...
0
votes
2
answers
2k
views
how to force linux to accept packet with loopback ip
i have an embedded system with an Ethernet interface that needs to accept external packets with IP of 127.x.x.xx. is there a way to force Linux to accept external packets with this loop back address ...
- 29
-4
votes
2
answers
87
views
How to manage PING replies? [closed]
How can I manage, for example, my Ubuntu mashine so it doesn't (or does) respond to PING(ICMP ECHO_REQUEST - type 8) requests?
Normally almost all computers in a LAN network responds to ping with an ...
- 235
0
votes
1
answer
2k
views
iptables blocking ability to ping/reach domain names
I'm trying to set up some firewall rules for allowing SSH, incoming ping, munin, and MySQL between one server and another (all those services are working fine with my rules), but when I apply the ...
- 1,367
4
votes
9
answers
18k
views
Why am I Unable to ping port 443 on Ubuntu?
I have opened port 443 through iptables:
pkts bytes target prot opt in out source destination
45 2428 ACCEPT all -- lo * 0.0.0.0/0 0.0.0.0/0
6 1009 ACCEPT tcp -- * * 0.0.0.0/0 ...
- 349
1
vote
3
answers
17k
views
Iptables: how to drop incoming pings from host but allow ping responses?
I am practicing with iptables and... I need a rule that will block a certain host from pinging me but will let me to ping the host if needed (so I need to accept ping responses right?). Can you help ...
- 258
2
votes
1
answer
4k
views
Ping O' Death and iptables
Is there a simple rule that can be written to stop a ping o' death with iptables?
- 2,276
2
votes
2
answers
515
views
How do you stop PINGs from causing a DOS on a Linux server?
Have a CentOS-5.x box that appears to be going down as a result of PINGs. If the server gets PINGs it stops replying to ssh/http connections. Appears iptable is one approach, but I want to make sure I'...
- 853